Experimental analysis of thermal performance of SAH with impinging jet having varying length of perforated jet plate

An experimental setup of an impinging jet solar air heater (IJSAH) was developed to study its thermal and frictional characteristics. Six cases were analysed with the jet holes spanning different lengths across the jet plate. For cases 1 and 2, jet holes spanned 100% and 80% of the length of the jet plate while having jet diameter equal to 3 mm. For cases 3,4, and 5, jet holes were drilled up to 100%, 80%, and 60% of the entire length and the diameter was increased to 6 mm. For case 6, jet holes were drilled up to 100% while keeping jet diameter equal to 9 mm. For each case, variation in Nusselt number, friction factor and temperature rise of the fluid was evaluated for Reynolds number in the range 4913 to 13,103. The efficiency and thermo-hydraulic performance factor with each case were compared. It was concluded that IJSAH with reduced length of drilled section (case 5) developed similar performance to IJSAH having completely perforated jet plate (case 1) while developing significantly lower friction factor. The temperature rise of the fluid and the friction factor developed for case 5 were around 10% and 40% lower than case 1, respectively.